You can configure a Switch to provide resilient links to another device so that network disruption is mini-
mized if a link fails. A resilient link pair consists of a
main link and a standby link. You define a resilient link pair by specifying the main port and standby port at one end of the pair.
Figure 4-13 Resilient link pair
Under normal network operating conditions, the main link carries your data. The Receive Idle signal of a fiber link or the Test Pulse on an Ethernet twisted pair link is continually monitored by the Switch. If a signal loss is detected, the Switch imme- diately enables the standby port so that it carries the data. In addition, the main port is disabled.
If a main link has a higher bandwidth than its standby link, traffic is automatically switched back to the main link provided no loss of link is detected for two minutes. Otherwise, you need to manually switch traffic back to the main link.
When setting up resilient links, you should note the following:
■ Up to four resilient link pairs can be configured
on a Switch 3000 FX.
■ Resilient links cannot be set up if Spanning Tree
(STP) is enabled on the Switch.
■ Resilient links can only be set up on fiber or
twisted pair links. The main and standby links in the same pair, however, can use any combina- tion of these media.
■ A resilient link pair can only be set up if:
■ The ports belong to the same VLAN.
■ Neither of the ports forms part of another
resilient link pair.
■ If the main port is a Virtual Lan Trunk (VLT) port,
the standby port must also be a VLT port.
■ A resilient link pair must be defined at only one
end of the connection.
■ You cannot disable any port that is part of a resil-
Configuring Resilient Links
With the Switch Management screen displayed, choose the port to be the main port in the resilient link pair, then select the RESILIENCE button.
The Port Resilience screen is displayed as shown in
Figure 4-14. This screen allows you to setup, edit and delete resilient link pairs.
The screen shows the following:
Main Port ID This read-only field displays the ID of the main port.
Media Type Twisted Pair / Fiber This read-only field displays the media type connected to the main port. Link State Available / Not Available / Not Present This read-only field displays the connection state of the main port:
■ Available — The port is operating normally ■ Not Available — The resilient link pair is disabled ■ Not Present — The port is not present in the cur-
rent hardware
Standby Port ID This field shows the current standby port ID and allows you to enter a new port ID. The standby port must be in the same VLAN as the main port.
Media TypeTwisted Pair / Fiber This read-only field displays the standby port media type.
Figure 4-14 Port Resilience screen
Link State Available / Not Available / Not Present This read-only field displays the connection state of the standby port:
■ Available — The port is operating normally ■ Not Available — The resilient link pair is disabled ■ Not Present — The port is not present in the cur-
rent hardware
Standby Links Available This listbox shows the ports that you can configure as standby.
Pair StateActive / Both Failed / Unknown / Not Available This read-only field displays the current operating state of the resilient link pair:
■ Active — The resilient link pair is enabled and
operating normally with both main and standby port capable of carrying traffic.
■ Both Failed — Although the resilient link is cor-
rectly configured, both links have failed. This could be due to loose connections or cable dam- age.
■ Unknown — The network configuration has
changed and the resilient link pair no longer con- forms to the rules.
■ Not Available — The resilient link pair is disabled.
Active Port Main / Standby If a main link does not have a higher bandwidth than its standby link, traf-
fic is not automatically switched back to the main
link when it recovers. Use this field to manually switch traffic back to the main link.
Pair Enable Enabled / Disabled Use this field to enable or disable the resilient link pair. Before you disable a resilient link pair, you must remove cabling from the ports to avoid creating loops in your network configuration.
Creating a Resilient Link Pair
1 Ensure that the port nominated as the standby port
is not physically connected to the unit.
2 Ensure both ports have an identical port security
mode configuration and that they are members of the same VLAN.
3 At the Switch Management screen, select the port
to be configured as the main port in the link. Select the RESILIENCE button at the foot of the screen.
4 Select the standby port from the Standby Links
Available listbox or enter the port ID in the Standby Port ID field.
5 Enable the pair in the Pair Enabled field. Select
APPLY.
6 Connect the cabling for the standby port.
Deleting a Resilient Link Pair
To delete the resilient link set up on the port, select the DELETE button at the foot of the screen. The Port Resilience screen closes and the Switch Man- agement screen is displayed.
Viewing the Resilient Setup
With the Switch Management screen displayed,
choose the management level Unit and select the
RESILIENCE button.
The Unit Resilience Summary screen is displayed as
shown in Figure 4-15. This screen shows the cur-
rent resilient link configuration for the unit, and allows you to access the Port Resilience screen for resilient link pairs.
The following read-only information is displayed: MAIN Port This read-only field displays the ID of the port configured as the main port for the resilient link pair.
STANDBY Port This read-only field displays the ID of the port configured as the standby port for the resilient link pair.
Pair State Active / Both Failed / Unknown / Not Available This read-only field displays the current state of the resilient link pair:
■ Active — The resilient link pair is enabled and
operating normally with both main and standby ports capable of carrying traffic.
■ Both Failed — Although the resilient link is cor-
rectly configured, both links have failed. Check for any loose connections or cable damage.
■ Unknown — The network configuration has
changed and the resilient link pair no longer con- forms to the rules.
■ Not Available — The resilient link pair is disabled.
Figure 4-15 Unit Resilience Summary screen
Active Port Main / Standby / Both Failed This read-only field displays which port in the resilient link pair is currently carrying traffic:
■ Main — The pair is operating in its normal state
with the main port carrying traffic.
■ Standby — The main port has failed and the
standby port is carrying the traffic. You should rectify the fault as soon as possible. If a main port has a higher bandwidth than the standby port, traffic is automatically switched back pro- vided no loss of link is detected for two minutes. Otherwise, switch the traffic back manually by setting the Active Port field in the Port Resilience
screen (described on page 4-19) to Main.
■ Both Failed — Both ports of the resilient link pair
have failed. This could be due to loose connec- tions or cable damage.
4-22 CHAPTER 4: MANAGING THE SWITCH 3000 FX
Pair EnableEnabled / Disabled This read-only field displays whether the resilient link pair is currently enabled or disabled. You enable or disable a resilient link pair using the Port Resilience screen described in
“Configuring Resilient Links” on page 4-19.
OK This button allows you to access the Port Resil-